Like a roving picaresque novel, the WikiLeaks diplomatic cables have been released since November in chapters, focusing on specific countries and distinct themes. When the anti-secrecy organization turned its focus to Cambodia last week  dumping nearly 800 missives from the U.S. Embassy in Phnom Penh online in 24 hours  the public was at last treated to a candid record of U.S. efforts to grapple with the rising influence of China here  and by extension in Southeast Asia as a whole.

When the Obama Administration took office in 2009, it was keen not to present itself as China's direct strategic adversary. Instead, officials said they were reviving American diplomacy in Asia while maintaining an aversion to "competition and rivalry" which could thwart cooperation with Beijing thirty years after it normalized relations with the U.S. But if it isn't competition and rivalry on display in the cables disclosed last week, it is something very near to it. Though the picture offered by the WikiLeaks archive is incomplete, with the bulk of material generated since 2006, the dispatches show a growing anxiety among U.S. officials about the inroads that Beijing is making in Cambodia. (Watch a video of WikiLeaks' founder Julian Assange on China.)

Beginning in 2006, the embassy began paying increasingly detailed attention to Beijing's relations with Phnom Penh. In April that year, the embassy was irked when Prime Minister Hun Sen praised a $600 million Chinese aid package announced during a visit by Chinese premier Wen Jiabao as coming "without strings." According to an unclassified cable, this was "a slap" at other aid donors, who, unlike China, placed conditions of accountability, reform and transparency on aid. "Despite all the hoopla... much of the assistance is old news and announced more than a year ago," said the cable. (Hun Sen has repeated this view in the years since.)

Four months later, the embassy briefed the State Department's human trafficking office after sending a Chinese-speaking intern and an official of Asian descent from its political/economic section to pose as customers at "sex establishments catering to the Chinese" where they queried managers, staff and Chinese businessmen. "Prices range from USD 20 to USD 150 depending on the type of service and ethnicity of the girl," a cable said. "At one bar, the manager tried to sell her daughter to" embassy officials.

By 2008, celebrations to mark the 50th anniversary of Cambodia's diplomatic relations with the People's Republic really caught the U.S. Embassy's attention. In late December, less than a month before President Barack Obama took office, the embassy cabled Washington with a breathless inventory of Chinese activities here. Describing a crescendo of lavish attention and warmth, the cable said China was set to achieve a "new apogee" in relations with Cambodia and the region: "Cambodia's 'Year of China' looks to become its 'Century of China.'" (See TIME's top 10 leaks.)

That year, King Norodom Sihamoni attended the Beijing Olympics and the Chinese Embassy hosted a royal banquet. China pledged $256 million in aid, mostly in soft loans, "the highest single-donor-country contribution to Cambodia ever." Foreign Minister Yang Jiechi had visited in February, announcing $55 million in aid and $1 billion in pledged commercial investment. New Chinese roads and dams proliferated, with China as the leading planner and financier of Cambodia's ambitious hydropower program that will have potentially devastating environmental consequences.

Though Hun Sen had claimed China's beneficence came with "no strings," it became clear in 2009 that the Chinese could call in extraordinary favors. That year, the Americans watched in dismay as, under heavy pressure from Beijing, Cambodian authorities flagrantly violated international law by wresting 20 ethnic Uihgur asylum seekers out of the U.N.'s hands and bundling them off to China where the faced execution for deadly riots in China's Xinjiang region. Within 48 hours, China had pledged $1.2 billion in assistance to Phnom Penh as an apparent reward. The U.S. Embassy swung into high gear, recording minute-by-minute the movements of Cambodian police, the apparent failures of the local and regional U.N. refugee agency officials and private confrontations with the Cambodian government.